I have two antennas/adapters, the T3U Plus and the T2U Plus. I was going to sell the T2U until I noticed the horrible performance of the T3U on macOS.
I have the last top of the line Intel Macbook Pro before Apple changed to Sillicon. I run it dual booted on Catalina and Win10. I've installed both adapters on both OS, thoroughly tested them, and noticed how badly optimized the T3U drivers are on macOS.
On Win10, both adapters perform as they should, with the T3U clearly having an edge over the T2U.
On macOS the T2U greatly outperforms the T3U. Even though the overall speeds of both adapters are not as fast as on Win10, the T3U is horrendous, barely half of the download speed of the T2U and about 1/4 of the upload speed.
It's inexplicable. And I can't install any other macOS drivers to test. Only the official ones. The beta drivers don't recognize the adapter, the same as these ones https://github.com/chris1111/Wireless-USB-Adapter-Clover
What can I do to solve this issue? It seems to be a problem related to drivers, since I can't replicate it on Win10, both adapters work well on that OS, and the T2U still performs as it should on macOS (even if a bit slower than on Win10). But the T3U is not working well on Catalina. Both the normal wifi and T2U perform way way better than the suposedly superior model T3U.